Missing tabs when using tao as base theme

Sounds like a template.php issue.

Tao divides tabs into the two variables, tabs1 & tabs2 in tao_preprocess_page. Like this:

  // Split primary and secondary local tasks
  $vars['tabs'] = theme('menu_local_tasks', 'primary');
  $vars['tabs2'] = theme('menu_local_tasks', 'secondary');

then it builds the markup like this:

/**
 * Override of theme_menu_local_tasks().
 * Add argument to allow primary/secondary local tasks to be printed
 * separately. Use theme_links() markup to consolidate.
 */
function tao_menu_local_tasks($type = '') {
  if ($primary = menu_primary_local_tasks()) {
    $primary = "<ul class='links primary-tabs'>{$primary}</ul>";
  }
  if ($secondary = menu_secondary_local_tasks()) {
    $secondary = "<ul class='links secondary-tabs'>$secondary</ul>";
  }
  switch ($type) {
    case 'primary':
      return $primary;
    case 'secondary':
      return $secondary;
    default:
      return $primary . $secondary;
  }
}

Make sure that you have both sets in TAO's template.php (in case you've edited it) and you have not overridden them in your own template's template.php.